As one of the necessities of humanity, ventilation is closely linked to the heating and illumination of spaces, and spaces such as in hospitals were among the first to need appropriately clean air for the health conditions of both patients and workers. In the different regions of Anatolia, many historic hospitals were built during the Seljuk and Ottoman periods. The primary function of those buildings was to take care of patients, yet in time they needed to care for themselves: so much so that only eleven of them are intact today, and just one continues to be used for its original function. Hence, this article presents the key ventilation and illumination practices applied over the centuries in those existing hospitals located in different regions of Anatolia and built during the 13th and 18th centuries; it also shows their influence on the architecture of the buildings in order to raise awareness of these issues in respect of their conservation. The study examines foundation archives and literature on the historic hospitals, including in situ observations, with a special focus on their ancient ventilation and illumination practices. The analysis reveals the similarities in and differences between these practices in the Seljuk and Ottoman periods. In addition, it assesses the potential conservation measures of these ancient passive survivability means used in Anatolian historic hospitals. The major conclusion of the study is that ancient ventilation and illumination practices may provide for the sustainability of historic hospitals in the long term and may, with the correct conservation solutions, contribute to their longevity.